Recently, systems for distributing content, such as music data or image data, to users via the Internet have been realized.
In such known DRM (Digital Rights Management) systems for protecting the copyright of works, the same protection method is used irrespective of the throughput of terminals. In particular, a low-throughput terminal or content storage device has difficulty in preventing unauthorized use of content.
In systems where a usage right and content are separately distributed, a terminal or content storage device has a great burden and difficulty of investigating the authenticity of both the usage right and the content and matching the usage right with the content. For example, it is difficult for a low-throughput terminal to determine whether a device has a usage right associated with content, investigate the authenticity of the usage right and the content, and permit use of the content to the device.